For the fellow audiophiles, a fix for the high pitched audio whine during pauses has been found. Update your phone to 5.5.893 <-- CLICK HERE . It includes some other fixes such as a better radio and whatnot.
I'm sure if you wait another month or so a real OTA update will fix it, but for those want better audio quality now, this is the way to go.
I believe this was mainly a problem with the higher end headphones. I am using a set of Shure SCL4's. Before the 5.5.893 update there was a high pitched whine due to interference from the 4gLTE antenna. After the update the issue is gone.